(node:896) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'substr' of undefined
    at Object.parseErrorMessage (F:\npm\node_modules\uncss\src\utility.js:171:30)
    at processWithTextApi (F:\npm\node_modules\uncss\src\uncss.js:144:23)
    at processTicksAndRejections (internal/process/task_queues.js:97:5)
(node:896) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:896) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.